Pneumatic impact-tool.



W. BURLINGHAM.

PNEUMA'TIG MPAGT TOOL.

APPLIGATION FILED MAR. za, 1m

Patented Jan. 5, 1915.

3 SHEETS-SHEET 1.

@WN Y f Mmm@ www S S S E N W W MTRMFEYS W. BURLINGHAM.

PNBUMATIC IMPACT TOOL.

APPLIOATION FILED MAR. 2a, 19144 Panted Jan. 5, 1915.

3 SHEETS-SHBET Z.

W. BURLINGHAM.

PNBUMATIG IMPACT TOOL.

APPLIGATION FILED MAR. 2a, 1914.

Patented. Jail. 5, 19 v15.

a SHEETS-SHEET a'.

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WITNESSES come of suilicient retrasar ortica WLLAM BURLINGHAIVI, 0F NEWPORT NEWS, VIRGINIA, ASSIGNOR OF ONE-HALE? T0 OF NEJVPORT NEWS, VXRGNIA.

'runuiua'ric maracas-Toon application inea March as, nur.

To uit whom t 72u13/ concern.'

Be it known that l, WILLIAM BURLING' naar, a citizen of the United States, residing at Newport News, county of WarViclnState or" Virginia, have invented a new anduseful Fneumatic llmpactflool, of which the following is a specification.

ln large industrial plants, such as shipyards, boiler-works, stone dressing plants l0.

and the like, where large numbers 'of pneumatic hammers for riveting, chipping, calking and kindred uses are constantly employed, the nishing, keeping up or increasing the compressed air equipment for the operation of said tools has become an important economical item in shop inanageu'ient, and the primary object, therefore, of my invention is to provide a novel construction of pneumatic hammer, having a novel fluid distribution system therein, whereby the cost of maintenance of the compressed air equipment is greatly reduced, and wherein the greatest possible ei'liciency can be attained with the greatest economy in the volume of .the motive fluid consumed. Formerly, when comparatively few pneumatic implements were used. in large plants, as even now in smaller establishments Where but a small number of such tools are used, the question of the quantity of the cubic volume ofair used was given but little consideration, as an air compressing plant supplying a suflicient amount of air under a given pressure could usually be erected at a reasonable outlay, and without occupying an' excessive area. llsually, the quantity of air consumed by the pneumatic hammering tools was more or less ignored, so long as the results in power of the tools is attained. At the present time, however, in large industrial plants, where pneumatic tools and other pneumatic appliances are extensively used, the size and initial expense of the air compressors and the space occupied by them, as Well as the power and fuel required for their daily operation, and the incident cost ofy their installation, operation and maintenance, have assumed proportions of such magnitude as to require careful attention, and have beimportance to require the careful consideration of remedies to reduce unnecessary expense in this connection. and

voil" that class wherein the problem of economically fun' portable,

speeiacanon of Letters :eaten-i.

Patented Jan, 5, tutti.. Serial No. Sl.

it is vwith the object of obtaining` much greater efficiency from a given volume of air at a given pressure in a pneumatic impact tool for riveting, chipping or analogous uses, that my novel `tpol is designed.

To the above ends, my iresent invention consists of a novel construction of a fluid distribution system. for portable, manuallv held pnemuatic impact or hammering tools, forward end of the cylinder is open forI the insertion of the shank of the working tool, and wherein the reciprocating piston or'plunger preferably hammers directly upon said shank, said plungerbeing actuated by air or other Huid, and said tools being employed particularly in metal work, such. as riveting, chipping, calking or hammering, and in all similar operations, wherein the use of a hammer or mallet and chisel have heretofore been employed.

In carrying out the'lroad principle of my present invention, .ll apply my novel Huid distribution system to' a pneumatic hammer, preferably of suoli size as to be and'manually held in the hand of. the user, the forward end of the tool cylinder being preferably adapted to be normally open and to have the shank oi' the chisel, button set or other lworking tool inserted therein, While my novel construction of differential reciprocating plunger which l employ, is adapted to hammer directly on said sha-nk.

ln carrying out my invention, I employ a novel construction of lpneumatic tool cylinder and its adjuncts' having a differential bore or piston chamber therein, said piston chamber being adapted for the reception of a novel plunger having diierential piston areas, in conjunction with which I employ a novel construction of coactinghigh pressure ,Y

rear end, the forward end of said tool cylin` der being preferably open. fonthe insertion,

novel construction of tolof the shank of the chisel, button set or other working tool. 'As a result of this collocation oi' high pressure inlet controlling and low pressure exhaust controlling valves, in combination with the receiver and my novel construction of ditferential pistonl chamber and hammering plunger proyided'with the differential piston areas, l am enabled to eiiect a savingof twenty per cent. overthe expense of operation of pneumatic tools now in use, and to utilize to a maximum extent the expansive eli'e'ct of the compressed air 'or the motive `duid which is initially used at high pressure, and l Afurther simultaneously employ high pressure live air and low prestion, l have saown in the accompanying drawings, one form thereof which is at present preferred by me, since the same will gire in practice satisfactory and reliable results, although it is to be understood that 4the various instrumentalities of which my sure air to augment the velocity or momene.' tum of the hammering plunger prior to or during the act of striking its blow directly upon the shank of the working tool. y

To the above ends, my invention therefore consists inits broad aspects, of a novel iiuid distribution system `for pneumatic hammers, wherein l utilize to a greater extent than heretofore, the expansive properties .of 'the 5 compressed air vemployed to evrect the reciprocations of the diidcrential plunger,

lilly intention iurther consists of a per cussion tool, wherein the compressed airis used espansively in a novel manner, so that so ,my novel construction of diierential hammering piston is inipelled directly upon the shank of the working tool during its striking blow by the high-pressure live-air and by low-pressure air simultaneously applied thereto.

lt further consists of a pneumatic hammer having a. novel construction of difieren l the high-pressure live-air is substantially 'only used for initiallyl impelling the di'erentialhannnering piston toward the working tool. l lt further consists of such a tool in which 5o high-pressure air is solely employed tor the hammering blow of the differential pistonel lt further consists et an improved arrangement of the operative parts of such s-,an impact tool, whereby the length of the ytool is reduced as compared with other tools of similar powerb A It further consists ot an improved construction ot' such a tool whereby the weight eo of the tool proportionate to its power is greatly reduced.

It further consists of other novel features of construction, all as will be hereinafter fully set forth.

For the purpose of illustrating-my inven,

invention consists can be variously arrz'inged and organized and that my invention is notl limited to theprecise arrangement and organization -olf these instrumentalities as herein shown and described. l

Figure l ,represents a diagrammatic view of the barrel, hammering plunger, valreeliambei's,f\fal\'es and passages of my improved iinpact tool, illustratingl the elements in' their respective positions when the plunger is at the beg-inning ol its hammering stroke.' Fig. 2 represents a. similar View of said elements, illustrating the same in their respective positions when the plunger is at the extreme of its hammerin,\' stroke. Fig. drepresents an axial section of one formel the tool Fig. 4- repr sents u, transe section oii the hainnie., taken on the line in Fig. il.

.Similar numerals of reference corresponding paris in the res.

Referring to the drawings, the reference numeral l indicates the barrel oi' the tool which has the usual arial bore` il, which forms the large-diameter working" cylinder and which has a toohsocket, 3, at .its lower end, or any other means Afor holding the shank of the `working tool, such as a rivet set, chisel, calking-tool or other percussion tool, and which cylinder forms the low-pressure and return cylinder. The upper open end of the barrel has a circumferential liange, el, engaged by an internally flanged coupling-sleeve, 5, formed with an internal screw-thread engaging the lower externally threaded end otl a handle-socket, (i, having a handle, 7, of any suitable or preferred form. The handle is here illustrated as ot the so-called closed type, and the couplingr may be of any other desired or preferred form commonly employed in lpneumatic hammers. rlie handle has a live-air inletnipple, 8, for the attaclnnent et the airhose, a live-air duet, 9, through it and controlled by a throttle-valve, l0, and a trigger, ll, for operating such valve. All of these parts mayv be of any preferred construction and design, being elements usually found in tools of this type and forming no part ol' my present invention.

'lhe lower end of the handle-socket which abuts against the upper end oiiethe' barrel, has preferably a reduced portion, l2, which fits into the upper end ot the large-diameter cylinder, and said socket has a smaller-diameter bore which forms the high-pressure working-cylinder, "i3, .in axial' alineinent with the large-diameter cylinder and closed indicate .at its upper end. A plunger is reciproeable in the two cylinders and has a cylindrical small-diameter piston, 14, having a sliding lit in the small-diameter cylinder, and a large-diameter piston, 15, at its lower end, having a sliding fit in the large-diameter cylinder and forming the low-pressure piston. rlhe small-diameter piston, which is the high-pressure piston, has a circumferential groove, 16, near its upper end, forming an annular distributing port, and a similar circumferential groove, 17, at a distance from its lower end and from theflargediameter piston, forming another annular distributing port. 'lwo enlargements, 18 and 19, are formed in the body of the/handle-socket and at one side of the same, being parallel to each other and to the cylinder in the socket, andl cylindrical valveblocls, 20 and 21, are secured in said housings and form respectively a high-pressure and a low-pressure valve-chamber, in which, respectively, a. high-pressure valve, 22, and a low-pressure Valve, 23, are slidable.

A receiver, 24, is provided in the tool and is formed, in the illustrated form of tool, by a number of longitudinal bores, 25, in the 'walls of the tool-socket and connected at their ends by annular chambers, 26. ln the diagrammatic views, Figs. 1 and 2, such receiver is illustrated as a plain cylindrical vessel.

The high-pressure valve-block 20 has a smaller-diameter bore, 27, and a larger-diameter bore, 28, and the upper end oi the large-diameter' bore has a port, 29, with which a distributing passage, 30, communicates, and the opposite end of said passage communicates through a port, 31, with the high-pressure cylinder at a distance from the upper end of the same.` rlhe large-diameter bore has an annular port, 32, which communicates through a distributing passage, 33, with the upper end of the high- .pressure cylinder. .An annular port, 34, surrounds the large-diameter valve-bore adjacent said latter port and communicates by a passage, 35, with the live-air inlet duct 9. A restricted port, 36, surrounds the lowermost end ol' the large-diameter bore and is constantly connected to the live-air duct by a passage, 37. An annular port, 38, surrounds the upper end of the smalldiameter bore and communicates by a passage39, with the upper end of the 'largediameter low-pressure cylinder. An annular port, 40, surrounds the small-diameter valve-bore and communicates 'through a passage, 41, with the receiver, 24. An annular port, 42, surrounds the lower-end of the small-diameter valve-bore and communicates through a` passage, 43, With a port, 44, in the high-pressure cylinder at about the middle of the same and is adapted to Abe uncovered by the sniall-diaiiietcr high-pressure piston of the plunger when the latter is at the extreme or' its downstrolre. The Valve which is slidable in the valve-chamber has two pistons, 45 and 46, which lit inthe large-diameter valvebore, and two pistons, 4T and 43, 'which lit in the small-diameter valve-bore.

The low-pressure mire-block .21 has a large-diameter bore, 49, and a small-diameter bore, 50, and the upper end et' such large-diameter bore has a port, 51, communicating through a passage, 52, and a port, 53, with the small-diameter highpressure cylinder at a point registering with the upper port-groove 16 in the upper end of the small-diameter high-pressure piston of the plunger, when the latter is atthe extreme of its down-stroke, and. a port, 54, in the high-pressure cylinder registers with said port 53 and with such port-groove, Iwhen the plunger is in said position, and communicates with the receiver through passage, 55. A port, 56,'eXtends from said passage 5.2 from the upper end of the largediameter low-pressure valve-lune into the small-diameter liigh-oressure cylinder and registers With a port, 57, in said cylinder communicating by an emiliaust-passage, 58, in the barrel with theatmosphere, and with a port, 59, in the cylinder and communicating by a passage, 6G, with the passage 30 connected to the upper end oli the highpressurc Yalve-cliainber. Said three registering ports are placed in communication by the annular port-groove 17 in the highpressure piston when the plunger is approaching the extreme of its rip-stroke or return-stroke as seen in. F l, so that the upper ends of both valve-chambers can multaneously exhaust. An annular eX- haust-port, 6.1, surrounds 'the upper end-of the large-diameter bore of the valve-chamber and communicates with the atmosphere, and an annular port, 6.2-, surrounds said ubore below the exhaust port and communicates with the louer end of the low-pressure cylinder by a passage, .An annular port, 64, surrounds the large-diameter low-pressure valve-bore below said latter port and communicates 'with the upper end olf the high-pressure cylinder through a passage, 65. at. restricted annular port, 66, surrounds the lower end of the large-diameter low-pressure valve-bore and has constant communication with the live-air inletduct by a passage, G?, An annular port, 63, surrounds the small-diameter low-pressure Valve-bore near its upper end,4` and communicates With the upper 'end of the largediameter low-pressure cylinder by a passage, in annular exhaust' port, 70, surrounds the small-diameter low-pressure Yalve-bore,'near the lower end of the same, and communicates with the atmosphere by a passage, Z1` ,The low-'m'essure valve 23 has two large-diameter pistons, 72 and Pi3,

and. o small-diameter pistons, 74 and 75, respectively slidable in the large-diameter and small-diameter valve-hores.

In explaining the operation 'of the hainmer, the several parts may be assumed to be in the positions illustrated in Fig. l of the drawings. When the high-pressure or liveair is admitted into the inlet-duct 9, such motive 'fluid passes between the t vo largediameter pistons 45 and 46 of the highpressurel valve which .is in its upper lposition, and into thempper end of the highpressure cylinder through the passage 33, forcing the plunger downward to deliver its blow upon the working tool. lllhatever air -is in the lower portion ol the low-pressure cylinder is forced out by the low-pressure piston through the passage ($3 to the port 62 ,in the large-diameter bore in the low-pressure valve-chamber, whence it exhausts through the upper exhaust-port (51 therein, ythe two large-diameter pistons 73 and 72 of the low-pressure valve, which is in its upper position7 connecting the port of said passage and the exhaust. When the highpressure piston in its down-stroke uncovers the port 3l in the high-pressure cylinder, the live-air passes through the passage 30 to above4 the high-pressure valve, forcing the same downward to the position illustrated in Fig. 2, cutting oii' the `live-air supply above the piston. The high-pressure piston, having gone down to the extreme of its down-stroke, has uncovered the port 44 and the expanding high-pressure air passes vthrough said port, through the passage 43 to the small-diameter bore of the high-prest sure valve-chamber, where the small-diameter valve -pistons 47 and 48, being in their. down position, connect the port 42 of said passage with 'the port 40 of the passage 41, and conduct the expanding air tothe receiver 24. As the plunger is in its down-position, the upper annular,

distributing groove 1G of the high-pressure pist-on connects the passage 55 and port 54 from the receiver with the port 53 and passage 52 to the upper end of the low-pressure valve-chamber, so that the air from the receiver forces the low-pressure valve down. This causes the expanding air above the high-pressure piston to flow through the passage to the large-diameter bore of the low-pressure valve-chamber, where the large pistons 73 and 7 2 now connect the port 64 of said passage tothe port 62 and. pa-ssage (i3, admitting the expanding air to the lower end of' the low-pressure cylinder where, acting against the larger piston area l5, it will force the plunger upward. The expanding live-air or high-pressure air above the high-pressure piston will also pass through the port 44, passage 43, ports 40 and 42, between thesniall pistons 47 and 48 of the high-pressure valve, and through` the passage 4l to the receiver 24.. The lowpressure air above the large piston exhausts through the passage 69,'ports ($8 and 70, which are connected. by the small pistons 7.5 and 74 of the low-pressure valve, and out to the atmosphere. When the plunger arrives on its 11p-stroke to the point where the lower annular distributing port 17 in the high-pressure piston connects the ports 56 and 59 from the upper ends ofthe valve chambers with the exhaust-port 57, the air above the valves' in such chambers is exhausted, and the live-air which is constantly admitted through the restrictedports 36 and G6 in tllervalve-chainbers, will exert the differential pressure against the larger and smaller areas of the two'middle pistons of the valves and, the pressure against the larger pistons prevailing, will move both of said valves upward, again repeating the operation. Asnow low-pressure air 1s stored -in the receiver, such air passes through the passage 41, ports 40 and 38, which are connected by the small valvepistons 47 and 48 in their upper position, see Fig.' l, and passage 39 into the upper end o'f the low-pressure cylinder, so that the expansion of this low-pressure air from the receiver also forces the plunger down-- Ward, adding strength to the blow. The air below the plunger freely exhausts through the passage 63 and ports 62 and G1 in the upper portion of the low-pressure valvechamber, in to the atmosphere, admitting of the plunger delivering an unobstructed blow.l

F rom the aboveit will appear that highpressure air and low-pressure air simultaneously cooperate to augment the operative down-stroke of the plunger, that lowpressure air, only, is employed to return the plunger, and that the valves are actuated in one direction by low-pressure air and in the opposite direction by constant live-air pressure without exhaust, and that the only exhaust is of low-presure air which has performed its functions, directly and expansively. After the high pressure air has forced the piston down to deliver the blow', a part of the expanding air is directly -employed to return the piston and a part is stored away inthe receiver to be employed to act against the low-pressure piston of the plunger in the driving stroke oi? the latter and to actuate the valves. No air ,is exhausted excepting the low -pressure air which has been used in the low-pressure cylinder and in the valve-chamber, so that high eiliciency is attained by using the air at its originaly pressure and thereupon again by compound use of the expanded low-pressure air exhausted from the high-pressure cylinder.

By `forming the receiver from longitudimanera l tial piston areas, the baclcstroke or upstrokel of such plunger is cushioned and shock of the 'tool reduced, easing the hold or the tool. to the Work.

lt has been, found `by tests and calculation, comparing hammers in use at present and my hammer that, taking the initial airpressure at one hundred and fifteen ounds (115 lbs), with a two inch stroke anj a cutoii atf, the old type hammer uses 12.4 cubic feet of air per minute, While my hammer v uses 9.82 cubic feet of air per minute, being a reduction 1n air consumption of 2.58 cubic feet per minute or 220.8%. With the old type hammer, using 12.41@ cubic feet per min nte, any energy of 14.17 footv pounds per strokcvis developed, while my hammer develops 16.51 foot pounds of ,energy per stroke when using' 9.82 cubic `feet of free air per minute. l`his is a. gain of 165% of foot pounds of energy on 2.58 cubic feet less air per minute y During the first six or seven strokes of the hammer, when startiiig the same after being idle, the receiver will not be quite charged lwith expanded air and the air therefrom vvill not have quite its full pressure, but after that time, a fairly constant pressure will be maintained.

While the down-stroke of the hammering plunger is performed on the compound principle, employing live-air and the partly eX- pan'ded air, or the action of high-pressure and low-pressure motive fluid combined, the compound principle is not employed for the return-stroke `which is performed by differential action of vthe expanded or lowpressure fluid.

@ther modes of applying the principle of my invention may be employed for the mode herein explained.l Change may therefore be made as regards the mechanism thus disclosed, provided the principles of construction set il'orth. respectively, in the following claims are employed.

It will be seen that by making the cylinler and handle-with its longitudinal extension, scimrable, the parts can be easily machined, and Aby the /eonjunction'of the handle and cylinder member, as seen in Fig'. 3, I readily iiorn'i" the differential piston chamber, lin which the differential hammering plunger or piston haying the diderential. piston areas reciprocates. By the emdirectly in unison -vvith ployment of the differential piston and cyl 65 Inder with my novel fluid distribution system, it Will be seen that l employ a c hamber 24 to receive the exhaust and also provide means for equalizing the air pressure in the high pressure cylinder and in the lovv pressure cylinder between the striking end of the dillerentia'l piston and the shank ot the working tool, thus utilizing the air in ,the high pressure cylinder after the receiver has beenI filled to return lthe piston;

'll desire to call special attentionto the lfact that my invention in its broad as ects is especially applicable to that type of ight or portable, manually held pneumatic 1mpact tools, especially adapted for riveting, chipping or Ward end of the differential piston chamber is open for the insertionoi 4the shank of the Working tool, and wherein the did'erential hammering piston impacts;v directly upon said shank of the rivet set, chisel or other working tool.

l am aware that it has heretofore been proposed to fuse compressed air somewhat as in a compound engine in rock drills or si1nilar structures, which employ massive and heavy rreciprocating engines frequently weighing several hundred pounds and which are required vto loe supported upon a Silitable tripod and wherein the drill or other Working tool is connected to or reciprocatcs the reciprocating pistonbut my present invention is clearly differentiated from massive tools of this character having a comparatively slovv moving piston, for the reason that-my present device is particularly applicable to the small manually held and controlled 'riveters or the ordinary compound engine in the matter of the motor fluid distribution. In a comanalogous uses, wherein the ior-` imi,

pound engine, the expanded fluid of the high f pressure cylindersafter the stroke has been completed, exhausts in itsentirety to its receiver during practically all of the-return stroke. in my device, the motor Huid distribution is quitedifferent. I take a part of the expanded air of the high pressure cylinder to the receiver, from this receiver the air is taken for shifting the low pressure valve, also-for the upper end of the high and 'low pressure cylinder to drive the piston down y on its Working stroke. The remainder of the expanded air left in the high pressure cylinder after the receiver is lled isused yto return the differential vplunger by a dit,

' 'spending scope awarded to 4a pioneer invenferential pressure upon the small and large pistons. rlf'he pressure ot this expanded air in the high pressure cylinder,'and the pressure in the cylinder on the hammer end of the piston, l equalize through a connecting passage.

It will be apparent from the diagrammatic \ieivs in Figs. l and 2, that the forward movement ot' the valves takes place at about' the saine time that the differential plimger is impacting upon the shank of the ivorliingtool, so that the impact of the striking lolon' serves to more firmly seat said valves in their` forward position at the proper periods, so that jumping or fluttering of the valves is avoidedu By the employment o the live air and partly expanded air upon the hammer or plunger, during the period it is. striking the blow, the velocity and momentum ot the reciprocating plunger is glreatly augmented during the period when such increase of poiver is desirable, and by the employment of the differential action of the expanded and loiv pressure fluid to return the hammering plun- ,ger after its impact against the shank of the working tool, the expansive action of the mo- "tive Huid is utilized tothe greatest extent. it will also be apparent that in my invention,by

the employment of the receiver and its adjuncts, the extensive lvibration heretofore incident to the operation of tools of this character, particularly during lriveting and chipping, is eliminated to a great extent. So i'ar as l am aware, l am theiirst in the art to .employ handle member having therein a `high pressure inlet controlling valve, a low pressure exhaust controlling valve, and a. receiver, either alone. or in conunction with the cylinder member having a larger bore therein, whereby a differential piston chamber is formed.r So far as l am aware, l am also the 'first inthe art to employ in a portable, manually held, pneumatic hammer, havingay cylinder provided with its front end open to receive the shank ot the Working tool, the features of the differential hammering plunger combined With the high pressure inlet controlling valve, the low pressure exhaust controlling valve,

and the receiver, whereby the motive' fluid" y may he used expansively as described in a pneumatic hammer of the character stated, and my claims to' these various features are therefore to be interpreted .with the corretion.

l claim as nenT and desire toseeu're by LettersPatent, isz-- a means' common to said cylinder, valve niech- Havingthus described my invention, what anism and receiver for operating by the pressure from said receiver, said valve mechanism, and for also ellecting the returning ol the piston to begin its stroke.

2. ln a pneumatic impact tool,v the combination of a cylinder, a piston therein, a valve mechanism, a receiver, and means for operating said piston and valve mechanism by means of the pressure ot the expanded air in the receiver.

ln a compound pneumatic impact tool', a small diameter cylinder, a large diameter cylinder, a small diameter and large dialneter piston adapted to reciprocate in said cylinder, and means for-using energy left in the air after it has been used iu one cylinder, 'for augmenting the energy oli' said piston.

L ln a compound pneumatic impact tool, a small diainetercylinder, a larger diameter cylinder, small diameter and larger diameter plungers adapted to reciprocate in said cyl.- inders, and means-for using the energy lett in the motive-fluid alter it has been used in 'any of the cylinders for 'augmenting the blow of said plungers.

5. ln a compound pneumatic impact tool having open ends, a plurality of cylinders of 'varying diameter, pistons oi' varying liameter adapted to lit said cylinders, and means 'foi-'utilizing the remainder o'li the energy leit in the expanded air after it has been'exhausted troin the initial pressure cylinder to increase the energy of the stroke of 'the piston without increase of consumption of the free air.

6. In a compound pneumatic impact tool, ay small-diameter and a large-diameter cylindei.' portion, a plunger `having a smalldiameter and a -largediameter piston -respectively reciprocable in said cylinder-V portions, a receiver, and high pressure linlet controlling valve, said small-diameter 'cylinder-portion, a receiver` means for admitting expanded inotive-iluid from said small-diameter cylinder-portion to such receiver, and means for admitting expanded motive-fluid from said receiver to a largediameter piston.

' S. In a pneumatic tool. a small diameter and a large diameter cylinder portion, a plunger having a large diameter and a small diameter piston, respectively, reciprocable in said cylinder portion` a receiver, means *for intermittently admitting motive-fluid into the, small diameter cylinder portion,

Slo

loa

eter cylinder after the receiver has means :for alternately admitting the eapanded Huid exhausted from the small diameter cylinder portion to 'the receiver, and means for equalizing the pressure ol the motive-fluid remaining in the small diam.-

heen iilled with motive-fluid, between the small diameter cylinder and 'the space in front of the large piston.

9. .lin a pneumatic impact tool, a Working-cylinder formed with a small-diameter portion and a large-diameter portion, a hammering plunger having a small-diameter and a large-diameter piston respectively slidahle iny saidcylinder vportions,A means for admitting motive fluid to said small-diameter cyliiidei} ioi-tior1, a receiver, :means for admitting expanded fluid from said small-diameter cylinder-portion to said receiver, and means connected to coperate with the motive fluid admitting means to substantially admit simultaneously eX- panded fluid from said receiver hack of the large-diameter piston. i

l0. ln a compound pneumatic hammer, a cylinder having a differential piston chamher forming high Yaressure and lovv pressure cylinders, plunger therein having high pressure and lov pressure piston areas, al receiver, a high pressure inlet controlling valve mechanism, means Acontrolled by the latter for simultaneously iltilizing live ino-n tive fluid on the high pressure area of said plunger and. expanded motive fluid from said receiver upon a large area of said plunger to drive said plungerdownwardly. il. l'n a compound pneumatic impact tool, a small-diameter and a large-diameter cylinder-portion, a plunger having a largediameter and a small-diameter piston respectively reciprocahle in said cylinder portions, means for intermittently admitting motive-fluid into the small-diameter cylinl der-portion, a receiver, means for conducting expanded motive-Huid exhausted` from the small-diameter cylinder-portion to said receiver., and means for alternately admitting expanded iluid exhausted from the snnilldiameter cylinder-portion to the opposite end oi the large-diameter cylinderportion. i 12in a compound pneumatic impact tool, a small-diameter and a large-diameter cylinder-portion, a. plunger having a small diameter and -a large-diameter piston rc-v spectively reciprocable in said cylinderportions, means -or intermittently admit- 'ting motive-'fluid into said small-diameter cylinder-portion, a receiver, means for conducting vexpanded iluid from said cylinderportion to said receiver, means connected to the motive-fluid admitting means 'to simultaneously admit lexpanded iluid from the receiver to the large-diameter cylinder-portion haclr out the' piston in the same, and

' fluid IBEW means for connecting the opposite ends of the cylinder-portions to admit of expanded differentially acting against the pistons.

1.3. ln a pneumatic 'impact'tooh a smalldiameter and a large-diameter cylinderportion, the latterhaving an openingA for the shank ol the Working tool, a plunger having a small-diameter and a large-diameter piston respectively reciprocahle in said cylinder-portions, passages .connected to the opposite ends of said cylinder-portions, a receiver, a high pressure inlet controlling valve arranged to intermittently connect said passages, and a loi7 pressure exhaust controlling valve for controlling the ex'- haust from said large-diameter piston.

14. In a pneumatic impact tool, a smalldiameter and a large-diameter cylinderportion, a plunger having a small-diameter and a large-diameter piston respectively reciprocable in said cylinder-portions, `a re-I ceiver, a passage from near the lower end of ,saidv small-diameter cylinder-portion t` said receiver, means for intermittently ad 90 mitting motive-fluid to the small-diameter cylinder-portion, a passage from saidreceiverA to the upper endl of the large-diameter cylinder-portion, and means coperating with such motive fluid admitting means and controllingn admission of expanded fluid from 'said receiver through Said pas sage to said cylinder-portion. l

15. ln a pneumaticimpact tool, a smalldiameter and .a large-diameter cylinderportion, a plunger having a small-diameter and a large-diameter .piston respectively reciprocahle in said cylinder-portions, 'a receivcr, a passage from near the Ylower end ot' said small-diameter cylinder-portion to 105 said receiver, means ior intermittently ad- .mitting motive-fluid to the small-diameter.

cylinder-portion, a passage from said receiver to the upper end of the large-diameter cylinder-portion;` means coperating with such motive fluid-admitting means and controlling admission or' expanded fluid from said receiver through said passage to said cylinder-portion, a passage between' the opposite ends of said cylinderp0rtions,' 115 and means in such passage controlling the same.

lli. ln a pneumatic impact tool, a smallvdiameter and a large-diameter cylinderportion, a. plunger having a small-diameter and a lange-diameterl piston respectively .reciprocable in said cylinder-- portions` means 'tor inteiiiiittently admitting motivefiuid into said snlall-diameter cylinder-por- ,Y tion, 'a receiver` a passage from nearthe 12 end "oi said small-diameter cylinder-portion to said receiver, a passage connecting said receiver and the upper end of the large-k diameter cylimler-portion, means for controlling said passage, an exhaust-passage romsaid upper end of said cylinder-portion, means for controlling said exhaustpassage, a passage connecting opposite ends of the cylinder-portions, and means for controlling such passage.

17. In a pneumatic tool, a cylinder hav-4 ing its forward end open and adapted to receive the shank of the working tool, said cylinder having a bore of dierent diameters, a differential plunger having pistons of dierent arcas, a receiver, and means for connecting 'opposite ends of such cylinder portions to allow expanded and exhausted fluid from a small diameter cylinder portion to act against the differential pistonL areas of said plunger.

18. In a pneumatic tool, ya cylinder provided with a 'differential piston chamber having'its front end open to receive the shank of. the working tool, a diiierential plunger in said cylinder, a high pressure valve chamber on said cylinder, a high pressure inlet controlling vvalve therein, a lou7 ressure valve chamber on said cylinder, a ow pressure exhaust controlling valve therein, and a receiver common to saidvalve chambers and piston chamber.

19. In a pneumatic hammer, a cylinder having its forward end ope'n to vreceive the shank of the working tool and provided with a diiierential piston chamber, whereby a high pressure and a low pressure-cylinder is formed, a differential plunger having a low pressure piston area therein, a receiver adjacent said cylinder, a low pressure exhaust controlling valve, means controlled by said valve for enabling exhaust from said levyl pressure cylinder to passte the atmospheue through said valve, and means controlled by said valve for simultaneously putting the high pressure cylinder and the chamber below said low pressure piston into communication, so that the pressure of the two chambers is equalized. 4

20. In a pneumatic hammer, a cylinder having its forward end open to receive the shank of the working tool and provided with a differential piston chamber, whereby a high pressure and a low pressure cylinder is formed, a dierential plunger therein, a receiver Iadjacent said cylinder, a low pressure exhaust controlling valve, means controlled by said valve for enabling exhaust y from said low pressure cylinder to pass to the atmosphere through said valve, means controlled by said valve for simultaneously putting the high pressure cylinder and the chamber below the low pressure piston into communication, so that the pressure of the two chambers is equalized, and a high pressure inlet valve mechanism for controlling the inlet and exhaust of motive fluid to said high pressure cylinder.

21. In a pneumatic impact tool, a difer ential valve-chamber having a large-diam- Lia-asas eter a small-diameter bore, a diierential valve having a pair of large and small di ameter pistons opposite ends thereof respectively reciprocable in said bores, said chamber having a constantly open motivefluid inlet port at the junction of the diilerent bores to admit such fluid to the differ ential areas of ay small and large diameter lpiston, and means for admitting and cxhausting fluid into and out of the end of the large-diameter bore.

22. In a pneumatic hammer, a cylinder having a differential piston chamber, the forward end of said cylinder being open for the reception of the shank of the working tool, a differential plunger in said piston chamber having pistons of diflerent areas, a receiver,`a high pressure inlet controlling valve 'for admitting air at initial pressure to thehigh pressure cylinder and the same time admitting air lfrom thereceiver to the low pressure cylinder, and a low pressure exhaust controlling valve -in connnuni cation with said receiver and said piston chamber.

Q3. In a pneumatic hammer, a cylinder having its forward end open for the shank of the working tool and provided with a differential piston chamber, whereby high' pressure andl low pressure cylinders are formed, a receiver adapted to receive the exhaust from the high pressure cylinder and retain it for use when required in the low pressure cylinder, a high pressure inlet con trolling valve, and a low pressure exhaust controllingvalve.

24h In a pneumatic hammer, a handle portion having an extension thereon forming portion of the piston chamber, a, cylinder member secured to said handle extension and bored to form continuation of said piston chamber,v a high pressure inlet con' trolling valve carried within said extension, a low pressure exhaust controlling valve carried within said extension, a receiver also located in said extension, and a piston in said piston chamber controlled by said valves.

25. In a pneumatic hammer, a cylinder member, a handle member having an extension thereon, means for securing said cylinder and handle member in assembled position, a high pressure chamber being formed in said handle extension, and a low pressure chamber being formed in said cylinder member, a differential hammering plunger, a high pressure inlet controlling valve, a low pressure exhaust controlling valve, anda receiver contained in said handle member.

26. AIn' a pneumatic hammer, a handle porltion having an extension thereon, and provided with a high pressure piston chamber, a cylinder member detachably secured to said extension, and provided with a low pressure piston chamber, a high pressure inlill controlled by said valves. i

let controlling and a low pressure exhaust controlling valve in said extension, a receiver also carried by said extension, and a dil'erential piston in said piston chambers 27. ln a pneumatic impact tool, a barrel formed with a large diameter cy inder portion, a handle socket connected to said barrel and formed with a small diameter cylinder portion, and a receiver consisting of longitudinal bores in the Wall of said vsocket around said cylinder-portion and connected trgether, a plunger having a large-diaineter and a small diameter piston respectively' reciproeable in saidv cylinder portions, and passages connecting the small diameter and the large diameter cylinder portions With said receiver, and means for controlling the lovvl of motive fluidl to and from said plunger.

28. lin a pneumatic hammer, a cylinder having a differential piston chamber, a differential plunger therein having grooves 16 and 17 thereinfand an enlarged head 15, a high pressure inlet controlling valve 22,have ing the enlarged heads 45 and 46 and the smaller heads 47 and 4S, a low pressure exhaust controlling valve 23, having the enlarged. heads 72 and 73 andA the smaller heads 74 and 75, means for conducting live motive iuid continuously to the space between the heads 48 and 45 and 73 and 74, a receiver, and ports and passages common to said piston chamber, receiver and valves,

29. ln a pneumatic hammer, a high pressure inlet controlling valve, having the dilferential heads 4S and 45, a loW pressure eX" haust controlling valve having the difierential heads 7 4 and 73, means for conducting live motive fluid constantly into the spaces between each of said heads, a receiver, a di'i'- i ferential piston chamber, a differential p1s-' ton therein, and ports and passages common to said receiver, valves and piston chambers.

30. ln a pneumatic hammer, a handlepbrtion having an extension thereon 'forming part of the piston chamber and bored to form a high pressure cylinder, a cylinder member secured to said extension and .hav-

ing a larger bore therein tol form a lovv pressure cylinder, a hammering plunger having diiierential piston areas contained respectively in said high pressure cylinder and said low pressure cylinder, means for permitting high pressure motive fluid to act initially in said high pressure cylinder, and means for simultaneously permitting the expanded motive fluid to act lupon a piston area in said low pressure cylinder to augment lthcforce of the plunger. Y

ln a pneumatic hammer, a cylinder member open at its forward end to receive the shank ci the Working tool and bored to striking blow of the form a 10W pressure cylinder, a handle member having an extension ,thereon with a bore therein of less diameter forming the high pressure cylinder, whereby a diii'crciitial piston chamber is formed, means 'loi' securing said cylinder member and handle lneinbei' together, a diiferential haii-imcring plunger having piston areas ot diil'erent diametcrs reciprocating in said differential piston chamber, a valve mechanism contained in the extension oi said handle member, and ports and passages common to said valve mechanism and said differential piston chamber for admitting and exhaustlng motive fluid therefrom.

32, In a pneumatic hammer, a -cylinder member open at its forward end to receive the shank oit the working tool and bore'd to form' a low pressure cylinder, a handle member having an extension thereon with a bore therein of less diameter forming the high pressure cylinder, whereby a difierential piston chamber isI formed, means for coupling said cylinder member and handle member together, a differential hammering plunger having piston areas of di ll'erent diameters reciprocating in said low pressure cylinder and said high pressure cylinder respectively, a high pressure inlet controlling y valve obtained inthe extension oi said handle member, a low pressure exhaust controlling valve also contained in said extension, a receiver also contained in said extension, and ports and passages common to said valves, receiver and the differential piston chamber.

` 33. In a pneumatic hammer, a cylinder member `open at its forward end to receive the shank of the Working tool and bored to form a low pressure cylinder, a handle memberliaving an extensionthereon with va bore therein of less diameter forming' the high pressure cylinder, whereby a differential piston chfmber is formed, means for coupling said cylinder member and haiidle member together, a diiierentialhaim mei-ing plunger having piston areas ofdifferent diameters reciprocating in said low' pressure cylinder and said high pressure cylinder respectively, said piston being provided with `grooves 16 and 17, a high pressureV inlet controlling valve contained in the extension or said handle member, a low pressure exhaust controlling valve also contained in said extension, a receiver also contained in said extension, and ports and passages common to said valves, receiver and the differential piston chamber.

34. ln a pneumatic hammer, a cylinder having its forward end open for the shank of the Working tool and provided with a diierential'piston '.chamber, wherebyY high pressure and lov.7 pressure cylinders are formed, a receiver adapted to rccei'iithe exhaust from the high pressure cylinder llllli and retain it for use when required in a e low pressure lcylinder, a high pressure inlet controlling valve, a low pressure exhaust controlling valve, ports and passages coiniiion to said valves, receiver and piston chamber, and mea-ns for causing live air pressure to constantly act upon a portion of each of said valves to shift the same.

35. ln apneumatic hammer, a cylinder member open 'at its forward end to receive the shank of the working tool and bored to forni a loW pressure cylinder, a handle member having an extension thereon with a bore therein of less diameter forming the high pressure cylinder, whereby a differ ential piston chamber is formed, means for 4securing said cylinder member and handle member together, a diflerential hammering plunger having piston areas of different diameters reciprocating in 'said ditlei'ential piston chamber, a valve mechanism contained in the extension of said handle inember, ports and passages common to said v valve mechanism and saiddifferential pis ing bored to form the high pressure cylinder, in combination with a cylinder inember, having a larger bore therein forming .the low pressure cylinder, whereby a differential piston chamber is formed, and a differential plunger in said piston chamber, controlled by said valves.

37. As an improved article of manufacture, in a compound pneumatic impact tool,

'a handle member having therein an inlet passage for the motive fluid, a high pressure inlet controlling valve chamber and a 10W pressure exhaust controlling valve chamber, said chambers being arranged on opposite sides of said inlet passage, said handle member also lia-ving an exhaust passage therein intermediate of said valves, and a receiver in the upper portion of said handle member, the latter being bored to forni 'the high pressure cylinder member of a compound pneumatic hammer.

38. In a compound pneumatic hammer, a handle member having an extension provided with a small bore forming a high pressure cylinder, a cylinder member attached thereto' and having a larger bore therein forming a low pressure cylinder, whereby a Liemers differential. piston chamber is formed, a differential plunger located in said piston chamber, and a valve mechanism for controlling the inlet and exliaustotl motive fluid to and from said piston chambers.

39. In a compound pneumatic hammer, a cylinder having therein a differential piston chamber, a differential plunger located in said piston chamber and having piston areas of different diameters, .a plurality of valves for controlling the inlet and exhaust of motive fluid to and from said piston chamber, and means` for causing live motive fluid to act constantly upon a portion of cach of said valves lor shifting the same.

40. ln a compound pneumatic hammer` a cylinder having its forward end open to re ccive the shank of the working tool and having a differential piston chamber therein, a differential plunger located in said piston chamber and having pistons therein el dif!- ierent diameters, a'vrec'civer, a plurality of valves for controlling the inlet and exhaust of motive fluid to and from said piston chamber, and means for causing live motive fluid to act constantly upon a portion of each of said valves for shifting the saine.

4l. ln a compound pneumatic hammer.v a cylinder having therein a differential pistou chamber, a differential, plunger located in said piston chainbe and having piston arcas of dillierent diameters, a receiver, and a valve mechanism for controlling the inlet and exhaust of motive fluid to and from said piston chamber, said valve mechanism com i'isin a liiralit of valves and means for 1 7 causing live motive fluid to constantly act upon a portion of. said valves for shifting the same. y

42. In a compound pneumatic hammer, a cylinder having its forward end open for the reception ot' the shank of the working tool, said cylinder having therein a difierential piston chamber, a differential plunger located in said piston chamber, a receiver, a plurality of valves for controllingr thc reciprocations of said piston, said valves having heads thereon of difi'erent diameters, and means for causing live motive fluid to act constantly upon the space between a pair of said heads of each valve for the purpose of shifting said valves.

43. In a compound pneumatic hammer, a cylinder member having its forward end open for the reception of the shank of a working tool, said cylinder having therein a ditlci'cntial piston chamber, a dill'ercntial plunger located in said piston chamber, a plurality of valves for controlling the reciprocations of said plunger, each of said valves having thereon two pairs of heads of difl'crcnt diameters, and means for causing,T livc motive fluid to act constantly upon the space between a small head and a large head of each of said valves for shifting the la ,icr.

:metiers Ziel, in a compound. pneumaticlhammer, a cylinder member having its forward end epen ior the reception of the Shank of a Working tool, said rylinder having therein a differential piston chamber, a difd'erential plunger `located in said piston Chamber, a plurality of valves for controlling 'thereciprocations of 'said plunger, each of said vulves haing thereon two pairs of heads oi diiferent diameters, means for causing live motive fluid te act constantly upon the space between a. small head and a large head each of said valves, a receiver', and ports und passages common to said valves, receiver and piston chamber.,

in a compound pneumatic hammer, a eyiinder member having its forward end open iter the reception oi" the shank of a Werl-:ing tool, said-cylinder having' therein a differential piston chamber, a d iii`erential piunger iocated` in said piston chamber, a plurality @if valves for controlling the reciproeations of said plunger, each of said valves having thereon tive peirs oi' heads 0i different diameters, means for causing live ,inotive iiuid to ect constantiy upon the space between a smali head 'and alarge head of each of said; valves, a receiver, and connections common to said receiver, piston chamber and one of said valves, whereby motive fluid 30 of said pluger to augment the momentum of '5 the striking blow of said plunger.

16. in a compound pneumatic impact tool, a plurality of Working cylinder portions oi' different diameters, a Working plunger having pistons of different diameters reciprocahle in said cylinder portion, means for admitting motive-huid to a small diameter cylinder portion, receivers, means for admitting expanded motive-Huid from said' cylinders to such receivers, and means for admitting expanded inotiveiiuid from said receivers to the cylinder portions of diiferent vdiameters to augment the blow oit' the piston.

W lLLAM BURLINGHAM.

Witnesses S. S. ARCHIBALD, JJ E; MCMEENAM.

juries t percent may he nbteiuecl fer jive cents euch, by addressing the Gommissioner et Biatents, Washington, XB.. G. 

